Usually, a so called EGR system consists of a tube or pipe connecting the interior of the intake conduit with that of the exhaust conduit of the engine, and a gas flow controller operatively disposed in the tube to control the flow rate of the gases passing therethrough in response to engine conditions.
Recently, due to the sake of reducing NO.sub.x emission, an internal combustion engine system for a motor vehicle is equipped with a so-called high EGR system by which a large amount of exhaust gases is fed to the intake of the engine system. In such an engine system, it is very necessary to arrange the EGR system such that only exhaust gases cleaned of some particles such as carbon particles are fed into the intake of the engine in order to prevent the tube of the EGR system from being plugged with such particles. In fact, the deposition of such particles in the tube cause a remarkable increase of flow resistance of the EGR system.
Thus, in a conventional high EGR system, the inlet opening of the system is located at a portion downstream of some exhaust gas purifying devices such as a thermal reactor and a catalytic converter because the exhaust gases having passed through such devices contain a minimum amount of carbon particles.
By using such a conventional EGR system, however, it is inevitably required, for accommodating the above-mentioned large volume of exhaust gas feed into the intake, that the tube or pipe of the EGR system is considerably long and considerably large in cross section. Thus, the whole structure of the engine system becomes bulky thus limiting the space of the engine room of the motor vehicle. Furthermore, the assemblage of such tube to the engine proper will be difficult due to the bulky construction of it.